Siemens S5-135U/155U - Manual (Page 408)

9-26
System Manual
C79000-G8576-C199-06
The resolution with Pt 100 resistance thermometers is approximately 0.25 o C.
1 ohm
10 units
Units Resistance in
ohms
Temper-
ature in
Byte 0 Byte 1
ohms ature in
o C
7
S
6
2 11
5
2 10
4
2 9
3
2 8
2
2 7
1
2 6
0
2 5
7
2 4
6
2 3
5
2 2
4
2 1
3
2 0
2
A
1
E
0
OV
4096 400.0 – 0 1 1 1 1 1 1 1 1 1 1 1 1 0/1 0/1 1 Overflow
4095
2049 399.90
200.98
–
269.1
0
0
1
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
0/1
0/1
0/1
0/1
0
0
Overrange
2048
2047 200.0
199.90
266.5
266.0
0
0
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0/1
0/1
0/1
0/1
0
0
1024
1023 100.00
99.90
0
–0.2
0
0
0
0
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0/1
0/1
0/1
0/1
0
0
Rated range
1
0 0.098
0.0
–
–
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0/1
0/1
0/1
0/1
0
0
A = Active bit
E = Error bit
OV = Overflow bit
S = Sign
When Pt 100 resistance thermometers are connected, the maximum
temperature in the rated range is 266
o C. If it can be ensured that the
temperature does not exceed 850 o C, the input value may extend into the
overrange. The resolution is then 4095 units. Unused inputs can be utilized
for voltage measurements in the 500 mV range (see front connector
assignments).
In addition to the standard Pt 100 range, there is an extended Pt 100 range on
the 460 analog input module. You can select this with the mode switch.
The following is printed on the cover of the module to set the Pt 100 mode:
Standard range: “resistance thermometer uncompensated full range”
Extended range: “resistance thermometer compensated low range”
In this range, the basic resistance of the Pt 100 at 0 o C (100 ohms) is
compensated for on the module. As in the standard range, the Pt 100 is fed
with a constant current of 2.5 mA. Using the overrange (- 100 mV to + 100
mV), this results in a temperature range of approx. -100
°
C to + 100
°
C.
This measuring range of 200
°
C is resolved to 8192 units with the correct
sign for the temperature. One unit thus corresponds to approximately 0.025
°
C. If you select the extended Pt 100 range, you can use all 8 analog inputs in
this range only.
You should only use the 6ES5 498-1AA11 range card (
$ 50 mV/500 mV).
Measured-Value
Representation for
Resistance
Thermometers in
the Standard Pt
100 Range
Extended Pt 100
Range
Analog Input/Output Modules